Optical frequency multiplication for low-phase noise microwave signal generation and delivery

We demonstrate the capability of optical frequency multiplication, or optical harmonic up-conversion to preserve the low phase noise of low-frequency microwave signals while optically up-converting their frequencies. We use the approach to transport and deliver a 17 GHz microwave local oscillator signal to a significantly simplified remote radio access unit, which is fed by single mode fibre, and multimode fibre, having a modal bandwidth below 1-GHz. Measurement results show that the remotely generated carrier has a very narrow linewidth below 20-Hz, and also exhibits lower phase nois